That is a valid point and Steemit, at present, is highly dependent upon the search engines.
Of course, I can counter that with the fact that decentralized search engines are on their way. There is one that I believe did their ICO and has the product in beta (I dont recall the name off the top of my head).
So the stranglehold on search is only temporary too.
People would simply get to know the website from online forums and word of mouth. Something similar was attempted on Russian new sites. It didn't have much of an effect and steemit is far more popular and my articles with less than 50 views had come up on the very first page in duckduckgo.